The "hacking" ("compromising" is probably a better word, since no real "hacking" is going on) being seen in D3 is no different than what World of Warcraft players have been seeing for five years or so. The sad thing is, if no one bought game currency (gold, credits, whatever) from these third-party companies, then essentially no account compromises would be occurring. Compromises not done by gold selling companies are very rare indeed. They strip one player to sell to another, because it's much more efficient than "farming" gold. They still farm some of course, but they do it purely with compromised accounts.

Unfortunately, these compromisers make a lot of money off of the practice (because players buy gold) and so they have a lot of resources to use to try to get your password from you directly, or through your computer. Some of their poorly translated phishing e-mails may be laughable, but their trojans, infected websites, etc. are not funny at all.

If you have the physical or mobile authenticator (both of which major banks use and charge $30+ for) the chances of you being compromised are very, very small. I've personally examined the MSInfo files of nearly all of the handful of WoW players who have actually been compromised through an authenticator, and the sheer number of backdoor programs and other malware on their systems has been mind boggling. Probably not coincidentally, these same people were also running a disturbing number of file-sharing and download programs, including ones which are commonly known to not be safe.

Again, compromising game accounts is a big business in some countries. They have people on their payroll who spread false rumors of "hacked through my authenticator" just to try to discourage people from using them. We charge $6.50 for the physical authenticator, because that's exactly what it costs us to make them. The mobile one is free because we don't have to pay a factory to build them. Use them, and enjoy your gaming without someone mucking with your stuff.